This page is updated on Wednesdays. Please see the GVP Home Page for news of the latest significant activity.The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.

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New Activity/Unrest

CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m

AVO reported that during 7-8 September clear-weather satellite views of Cleveland showed no thermal anomalies or recent deposits on the flanks. The Volcano Alert Level and the Aviation Color Code were lowered to Unassigned. On 11 September, a thermal anomaly was observed in satellite imagery. The next day a possible ash plume seen in satellite imagery rose to the estimated altitude of 7.6 km (25,000 ft) a.s.l. and drifted E. The Volcano Alert Level and the Aviation Color Code were again raised to Advisory and Yellow, respectively. A thermal anomaly was again visible during 13-14 September.

Geologic Summary. Symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.

Source: Alaska Volcano Observatory (AVO)

Cleveland Information from the Global Volcanism Program

EKARMA Kuril Islands (Russia) 48.958°N, 153.93°E; summit elev. 1170 m

On 13 September, SVERT reported that strong steam-and-gas activity from Ekarma continued. Ekarma does not have a seismic network; satellite image analysis and infrequent ground observations are the primary tool for monitoring many of the Kuril Islands volcanoes.

Geologic Summary. The small 5 x 7.5 km island of Ekarma lies 8.5 km north of Shiashkotan Island along an E-W-trending volcanic chain extending westward from the central part of the main Kuril Island arc. Ekarma is composed of two overlapping basaltic-andesite to andesitic volcanoes, the western of which has been historically active. Lava flows radiate 3 km in all directions from the summit of the younger cone to the sea, forming a lobate shoreline. A lava dome that was emplaced during the first historical eruption, in 1776-79, forms the peaked, 1170-m-high summit of the island. The only other historical eruption produced minor explosions in 1980.

KVERT reported that during 3-10 September seismic activity from Kliuchevskoi was above background levels and lava flowed down the SW and NW flanks. Satellite imagery analyses showed a large and intense daily thermal anomaly over the volcano. During 2-4 September ash plumes seen in satellite imagery drifted 150 km S and SW at an altitude of 6.5 km (21,300 ft) a.s.l. Phreatic bursts on the SW flank were observed on 5 September and Strombolian activity was seen during 5-7 September. Seismic data suggested that during 5-6 September ash plumes rose to an altitude of 6 km (19,700 ft) a.s.l.

Based on analyses of satellite imagery, the Tokyo VAAC reported that a possible eruption on 12 September produced a plume that rose to an altitude of 7.6 km (25,000 ft) a.s.l. and drifted SE. On 13 September an ash plume rose to an altitude of 9.8 km (32,000 ft) a.s.l. and drifted NE according to information sent from the Yelizovo Airport (UHPP). Ash was seen in subsequent satellite images during 13-14 September. The Aviation Color Code level remained at Orange.

Geologic Summary. Kliuchevskoi is Kamchatka's highest and most active volcano. Since its origin about 7,000 years ago, the beautifully symmetrical, 4,835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. More than 100 flank eruptions, mostly on the NE and SE flanks of the conical volcano between 500 m and 3,600 m elevation, have occurred during the past 3,000 years. The morphology of its 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included major explosive and effusive events from flank craters.

The Popayán Volcano Observatory (INGEOMINAS) reported increased activity from Nevado del Huila on 8 and 9 September. Pulses of tremor were associated with periodic emissions of gas, ash, and incandescent material observed with the Tafxnú and Maravillas web cameras. During 8-14 September plumes of steam and occasionally ash rose as high as 2 km above the summit. The Alert Level was raised to II (Orange; "probable eruption in term of days or weeks").

Geologic Summary. Nevado del Huila, the highest active volcano in Colombia, is an elongated N-S-trending volcanic chain mantled by a glacier icecap. The andesitic-dacitic volcano was constructed within a 10-km-wide caldera. Volcanism at Nevado del Huila has produced six volcanic cones whose ages in general migrated from south to north. Two glacier-free lava domes lie at the southern end of the Huila volcanic complex. The first historical eruption from this little known volcano took place in the 16th century. Two persistent steam columns rise from the central peak, and hot springs are also present.

SERNAGEOMIN reported that an overflight of Planchón-Peteroa on 7 September revealed that the explosions the day before were possibly phreato-magmatic in origin and similar to the explosions in 1991. Pulses of gas and ash had occurred every 40-60 seconds during the eruption. Plumes rose 200 m above the crater and ash mostly fell within 10 km to the E. During 10-13 September, plumes rising from the vent had progressively less ash and higher concentrations of water vapor. On 13 September, SERNAGEOMIN reported that petrographic and mineralogical studies of the ash indicated no juvenile components. The Alert Level remained at 4, Yellow.

Geologic Summary. Planchón-Peteroa is an elongated complex volcano along the Chile-Argentina border with several overlapping calderas. Activity began in the Pleistocene with construction of the basaltic-andesite to dacitic Volcán Azufre, followed by formation of basaltic and basaltic-andesite Volcán Planchón, 6 km to the N. About 11,500 years ago, much of Azufre and part of Planchón collapsed, forming the massive Río Teno debris avalanche, which reached Chile's Central Valley. Subsequently, Volcán Planchón II was formed. The youngest volcano, andesitic and basaltic-andesite Volcá Peteroa, consists of scattered vents between Azufre and Planchón. Peteroa has been active into historical time and contains a small steaming crater lake. Historical eruptions from the Planchón-Peteroa complex have been dominantly explosive, although lava flows were erupted in 1837 and 1937.

Geologic Summary. Symmetrical, forest-covered Santa María volcano is one of a chain of large stratovolcanoes that rises dramatically above the Pacific coastal plain of Guatemala. The stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 1-km-wide crater, which formed during a catastrophic eruption in 1902 and extends from just below the summit to the lower flank. The renowned Plinian eruption of 1902 followed a long repose period and devastated much of SW Guatemala. The large dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four westward-younging vents, accompanied by almost continuous minor explosions and periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.

CVGHM reported that during 8-11 September Sinabung emitted white-to-gray plumes that rose 30-100 m above the crater and generally drifted E. Deformation measurements during 8-14 September showed a slow rate of inflation. Based on analyses of satellite imagery and the CVGHM web camera, the Darwin VAAC reported that on 12 and 14 September ash plumes rose to altitudes of 4.3-4.6 km (14,000-15,000 ft) a.s.l. The Alert Level remained at 4 (on a scale of 1-4).

Geologic Summary. Gunung Sinabung is a Pleistocene-to-Holocene stratovolcano with many lava flows on its flanks. The migration of summit vents along a N-S line gives the summit crater complex an elongated form. The youngest crater of this conical, 2460-m-high andesitic-to-dacitic volcano is at the southern end of the four overlapping summit craters. An unconfirmed eruption was noted in 1881, and solfataric activity was seen at the summit and upper flanks of Sinabung in 1912, although no confirmed historical eruptions were recorded prior to 2010.

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